iOS Swift: UIPageViewController - Turning page programmatically

Question

I have a UIPageViewController, which works fine when we swipe left or right to turn pages.

class ViewController: UIViewController, UIPageViewControllerDataSou         


        

Answer 1

Here is the swift 4 implementation with the delegates as well.

Since I also use the UIPageViewControllerDelegate, and the delegate methods weren't called with most of the setViewController solutions.

Thanks to Andrew Duncan's for his comment about the delegate.

// Functions for clicking next and previous in the navbar, Updated for swift 4
@objc func toNextArticle(){
    guard let currentViewController = self.viewControllers?.first else { return }

    guard let nextViewController = dataSource?.pageViewController( self, viewControllerAfter: currentViewController ) else { return }

    // Has to be set like this, since else the delgates for the buttons won't work
    setViewControllers([nextViewController], direction: .forward, animated: true, completion: { completed in self.delegate?.pageViewController?(self, didFinishAnimating: true, previousViewControllers: [], transitionCompleted: completed) })
}

@objc func toPreviousArticle(){
    guard let currentViewController = self.viewControllers?.first else { return }

    guard let previousViewController = dataSource?.pageViewController( self, viewControllerBefore: currentViewController ) else { return }

    // Has to be set like this, since else the delgates for the buttons won't work
    setViewControllers([previousViewController], direction: .reverse, animated: true, completion:{ completed in self.delegate?.pageViewController?(self, didFinishAnimating: true, previousViewControllers: [], transitionCompleted: completed) })
}